Open-jet filling systems and related methods are known from the prior art. In particular EP 1 571 119 A1 already discloses an open-jet filling system in the case of which the filling element and the container opening are spaced apart during the filling process so that there will be no contact between the filling element and the container; this has advantages from the hygienic and micro biological points of view. The open-jet filling element is provided with a filling level probe which is adapted to be introduced in the container by means of a probe actuator. In order to pinpoint the bottle mouth, the probe is implemented as an angular component. In the embodiment disclosed, the treatment of plastic containers consisting of polyethylene terephthalate (PET) is unproblematic, since these containers have dimensionally accurate container mouths and can be centered precisely below the filling element by means of neck-handling clamps.
A problem which now arises in connection with these known open-jet filling systems is that other containers cannot easily be centered sufficiently precisely with respect to the open-jet filling element. This concerns in particular plastic containers consisting of polyethylene (PE), which, as a result of the manufacturing process employed, are subject to strong variations in the three dimensions. When these containers are transported through the filling machine in a so-called base handling mode, they are supported from below by a transport table and radially from the side by format parts. Through deviations occurring in a horizontal direction that is radial to the axis of rotation of the machine, deviations between the vertical filling element axis and the vertical axis through the centre of the container mouth may occur. This has, on the one hand, the effect that the product jet will not precisely target the bottle mouth thus causing a hygienic risk at the filled bottle as well as at the surrounding machine parts. On the other hand, it may happen that the insertable probe fails to target the bottle mouth precisely, being damaged thereby, whereby an exact measurement of the filling level will no longer be possible.
This problem is normally solved by a centering means in the case of which an annular component, which is arranged below the filling element such that it extends coaxially therewith, is applied to the bottle mouth prior to the filling operation, whereby the bottle mouth will be centered exactly below the filling element.
Another problem arising is that, when base handling is used, it is, due to variations of the bottle height, impossible to realize a constant filling level when seen from the bottle mouth. Even if neck handling is used, different filling levels may be obtained due to variations of the mouth height, measured from the carrier ring to the bottle mouth, since these variations cannot be discerned by the probe actuator of the movable probe. It follows that the known system adjusts only one filling level for containers that are not dimensionally accurate, said filling level being e.g. measured from the lower edge of the filling element to the probe tip, but not from the container mouth.